Large roller chains with mounted cutting elements are used to dig trenches in the ground much in the same manner as a chain saw cuts wood. As can be imagined, the digging chain used to this purpose is very large and robust in order to absorb the forces necessary to dig a ditch between one and two feet wide to a depth of, for example, several feet in a single pass. The Charles Machine Works, Inc., assignee of the present application, has manufactured machinery of this type for many years.
A typical ditch digger will have an extended arm which is pivoted at its inner end to the machine. The inner end of the arm mounts a drive sprocket gear and the outer end an idler sprocket gear. A chain with suitable cutting elements or teeth is mounted between the gears and driven by the drive gear. A suitable device, such as a hydraulic ram, pivots the arm into the ground with sufficient force so that the teeth on the chain dig a trench of the desired width and depth. The device will move slowly forward as the trench is dug until the final length of the ditch is achieved.
As can well be imagined, the digging chain is an element of critical design and high wear. A need exists for constantly improving the design and service life of such a chain.